In this thesis I present my work in the field of SDR (Software Defined Radio) and concurrent systems. This work is part of the hybrid SDR Platform project, which distributes the signal processing between the Central Processing Unit of the PC (Personal Computer) and a dedicated signal processor. The PC side of the platform is the controller and the human interface of the system. It is a translator between the wishes of the user and the dedicated signal processor. As it is purely software we labelled it SP (Software Platform). The dedicated signal processor, together with the analogue RF (Radio Frequency) front-end and high speed signal converters is the HP (Hardware Platform). My share of this endeavour was the development of the SP (Software Platform) of the SDR Platform. The concept of the SDR Platform is to not limit the user to a specific HP (Hardware Platform). In real-time signal processing, the signal processing algorithms execute concurrently. To implement the algorithms I chose to use Communicating Sequential Processes, which with its processes and channels resembles block diagrams, visualising signal processing chains. The SP itself is a concurrent system as well, thus I use CSP (Communicating Sequential Processes) as the basis for the SP. The SP consists of the management and the exchangeable SM (Software Module) part. To exchange a SM it is first necessary to terminate the process network representing it. One way of terminating process networks is to spread a termination message (poison) through it, informing every process about the termination. I extended the graceful termination technique, by introducing a second type of poison. I developed a proof of concept implementation, JCSP-Poison, which is based on JCSP. I show the CSP models of these channels as well as verifying that the JCSP implementation of them works correctly. I developed KCSP (Kernel Communicating Sequential Processes), which is an add on to an OS kernel, providing a CSP environment. KCSP allows developers to develop device drivers following the CSP principles.